(See also Meningitis)
Encephalitis is an inflammation of the brain, usually caused by a viral infection. Although rare, it is potentially life-threatening, and may lead to permanent brain damage or death.
Many different viruses can cause encephalitis, including the herpes simplex virus (HSV - which also causes cold sores) and enteroviruses. In some cases infections are caused by mosquito bites (e.g. Murray Valley encephalitis, also known as Australian encephalitis; equine encephalitis). A milder form of encephalitis can also accompany some of the common childhood diseases such as chicken pox, measles, mumps, and rubella (German measles).
Symptoms may include a high fever and headache, accompanied by a stiff neck, vomiting, light sensitivity, and convulsions. Patients may also be drowsy, or confused, and difficult to rouse. In babies, there may be a bulge in the fontanelle.
Many of these symptoms also occur in other illnesses (e.g. migraines), so the presence of fever is an important indication.
Most patients are admitted to hospital, and treatment will depend on the diagnosis of the cause. Anti-viral or anti-bacterial medicines may be prescribed, along with other medications to relieve the symptoms, such as corticosteroids to reduce inflammation, anti-convulsants, and medications for pain relief.
The prognosis for a person with encephalitis varies according to the age of the patient – with the very young and very old particularly at risk – and the particular virus that caused the disease. While many people make a full recovery, in severe cases, the illness may be fatal or result in brain damage.
Further Information and Support
Read more at Virtual Medical Centre
National Institute of Neurological Disorders and Stroke
British Brain and Spine Foundation
The Encephalitis Society (UK)
Reviewed by: Dr Matthew Kiernan, PhD, FRACP, Consultant Neurologist, Prince of Wales Hospital